The present invention relates to a packet for long articles.
The invention relates in particular to a packet for products designed for smoking, such as cigarettes or cigars, to which the specification below refers but without thereby restricting the scope of the invention, and applies to both soft and rigid packets.
Normally, soft cigarette packets have a substantially parallelepipedal shape and consist of an inner wrap made of paper or-foil, placed right around a group of cigarettes, and an outer wrap or label made from a length of wrapping material, usually paper, placed partly around the first wrap in such a way as to leave the top end of the latter free.
Similarly, rigid cigarette packets are also substantially parallelepipedal in shape and consist essentially of a box-like outer wrap made from a ready-weakened flat blank, usually paperboard, designed to contain an inner wrap, usually paper or foil, holding a group of cigarettes and identical to the inner wrap used for soft packets. The box-like outer wrap usually comprises a cup-shaped container, a lid, also cup-shaped, hinged to a rear edge of the container and an inner frame placed partly inside the container and attached to the front sidewall and to two lateral sidewalls of the container itself.
Normally, the outer wrap has a revenue stamp on it, which may be applied in many different ways according to diverse requirements, and in some cases, packets of the type described above include inserts such as cards, coupons, or similar items, bearing text, figures, or, more often, images which constitute messages of various kinds directed at consumers.
Both the inner wrap and the outer wrap, whether the latter is made from a length of wrapping material or from a ready-weakened flat blank, constitute specific packaging components of the respective type of packets, while the stamp and insert are additional components.
Cigarette packets of the type described above are also wrapped and sealed with a protective overwrap made from transparent plastic film, for example, polypropylene, equipped with a tear strip designed to enable the overwrap to be easily torn in order to gain access to the outer wrap to open the packet of cigarettes.
In the cigarette packaging industry, the outer wraps of the packets have messages or bar codes printed on the outside of them which can be read using optical scanners without opening the packets. These messages or bar codes provide information such as the type of product contained, the place of manufacture, the date of production, and other data which can be used by distributors to organize and manage their stocks.
Since these informative messages and codes are usually relatively large and, if printed directly on the outside of the packet, interfere with the trademarks appearing on the packet, it is now common practice, according to patent EP 317,202, to use in their place a magnetic strip as tear strip or sealing strip. The strip is of the same type as the tape used in the audio or video recording sector, and has data recorded on it using conventional magnetic recording technology in a form which can be read by magnetic reading equipment. Strips of this kind are applied in visible parts of cigarette packets or of finished products in general. In the case of cigarette packets in particular, the tear strip is applied directly to the polypropylene of the protective overwrap in a position that is clearly identifiable and visible from the outside.
In the tobacco industry, conventional non-magnetic tear strip is usually applied to the plastic overwrap by thermosealing. As is well-known, this has the disadvantage created by the high thermal inertia of the sealing devices, which must be heated to high operating temperatures in order to effect sealing correctly even at the high operating speeds of current packaging machinery which allow the tear strip and wrapping material to remain in contact with the sealing devices for a very short time.
The heat regulation system must therefore be extremely sophisticated and precise in order to prevent critical temperatures from being reached, as such temperatures cause the tear strip and wrapping material to melt if the tear strip and wrapping material are not fed at the optimum rate and thus remain in contact with the sealers for longer lengths of time.
This constitutes an even greater problem if the tear strip is made of magnetic material. Thus, even if the temperature of the sealers can be regulated accurately enough to correctly thermoseal a conventional tear strip to the overwrap without reaching critical temperatures, in the case of a tear strip with magnetic properties, the sealing temperature, even if perfectly regulated, may cause weak thermal stresses that destroy the magnetizing properties of the tear strip itself or, in the case of information recorded on the tear strip before it is thermosealed, may corrupt the information, thus making it illegible.